Power transmission



March 1, 1966 L.. v. REAUME POWER TRANSMISSION 4 Sheets-Sheet l OriginalFiled Jan. 14, 1959 INVENTOR LEONARD V. REAUME ATTORNEYS March l, 1966L, v REAUME POWER TRANSMISSION 4 Sheets-Sheet 2 Original Filed Jan. 14,1959 FIG. 9

INVENTOR ATTORNEYS March 1, 1966 L v REAUME 3,237,569

POWER TRANSMISSION Original Filed Jan. 14, 1959 `@Sheets-Sheet 5 BY/ rMAX/uli@ 5./

ATTORNEYS 55 @j 52 LEO/NARD v. REAUME FIG. 6

March 1, 1966 v REAUME 3,237,569

POWER TRANSMISSION Original Filed Jan. 14, 1959 4 Sheets-Sheet 4INVENTOR l J |32J Z|34 |32j LEONARD v. REAUME FIG. I6

ATTORNEYS United States Patent O 3,237,569 POWER TRANSMISSION Leonard V.Reaume, Clawson, Mich., assigner to Sperry Rand Corporation, acorporation of Delaware Original application Jan. 14, 1959, Ser. No.786,734, now Patent No. 3,185,104, dated May 25, 1965. Divided and thisapplication Dec. 20, 1962, Ser. No. 246,138 6 Claims. (Cl. 10S-162) Thisapplication is a division of applic-ation Serial No. 786,734 tiledJanuary 14, 1959, in the names of John T. Burns, Clarence E. Liles, CarlR. Potter and Leonard V. Reaume, now Patent No. 3,185,104.

This invention relates to power transmissions and is particularlyapplicable to those of the type comprising two or more iluid pressureenergy translating devices, one of which may function as a pump andanother as a lluid motor.

The invention is generally concerned with fluid pumps or motors of therotary axial piston type and, in particular, with an improved variabledisplacement device of this type. For the purposes of convenience theinvention will be described as a uid pump, but it should be understoodthat the term pump when used hereafter in the specification and claimsembraces both a fluid pump and a uid motor.

Such devices comprise a casing within which is a rotary cylinder barrelhaving a plurality of parallel cylinder bores within which pistonsreciprocate, the pistons extending from the cylinder barrel to eitherdirectly abut camming means, such as a thrust plate member, or beingassociated therewith by means of articulated connecting rods. Thecylinder barrel rotates against a valve plate having inlet and outletports which serves in a well-known 4manner to provide properly phasedcommunication between the end Iports of the cylinder bores, within whichthe pistons reciprocate, and inlet and outlet passages of the device.Examples of the type of devices described are disclosed in the patentsto I. Martin, No. 2,404,309; to R. Ianney, No. 1,020,285, and to A.Keel, No. 2,776,628.

In such devices the axis of the thrust plate member is inclined relativeto 'the axis of rotation of the cylinder barrel for reciprocating thepistons, the total displacement of the device being resolved by therelative angle of inclination between the axes of the two members, sincethe displacement of each piston is determined by the area of thecylinder bore and the length of stroke of the piston, and the length ofstroke of the Ipiston is determined by the relative angle -ofinclination of the axis of rotation of the cylinder barrel and the axisof the thrust plate member.

It has been the practice, therefore, to vary the displacement of suchdevices by providing a swinging yoke for changing the angle of tilt ofthe cylinder barrel to vary piston stroke length or by providingmechanism for changing the :angle of tilt of the thrust plate member tovary piston stroke length. The yoke or other mechanism may be manuallyor fluid pressure operated. Examples of two such forms of variabledisplacement devices are disclosed in Patents No. 2,565,208 to l.Dietiker and No. 2,708,879 to T. Van Meter.

Rotary axial piston devices of the type described have been on themarket for years and have been proven to be successful, being moreadaptable and eicient than other forms of fluid energy translatingdevices, such as sliding vane and gear type devices, for extremely highspeed and high pressure applications, for example, the driving ofaircraft accessories. I-t should be noted, however, that variabledisplacement, rotary, axial piston devices of the type described, areconsiderably greater in size and weight than corresponding units of thefixed displacement type Fice and, of course, are appreciably greater incost. Although the fixed displacement versions 0f the two types ofdevices for the same maximum displacement may be relatively compact landuncomplicated, the variable displacement units are substantially largerand more complex in structure than the fixed displacement units becauseofthe variable displacement actuating mechanism and elements associatedtherewith, such as pintles for the swinging yoke. Another factorcontributing to their increased size is that the casing must be madelarge enough to provide space for freedom of swinging movement of theyoke and cylinder barrel or of the tiltable thrust plate member and itsassociated actuating mechanism.

Thus, savings in manufacturing costs and consequent reduction in thesales price, which could be accomplished by making both the casings andthe rotary pump and motor assemblies mounted within such casingsbasically the same for both iixed and variable displacement types ofunits, are not achieved because of the necessity of providing casings ofa different size and entirely different construction for the fixed andvariable displacement units.

Still other forms of variable displacement, reciprocating piston, uidenergy translating devices :have been devised wherein the displacementis varied by means other than changing the length of stroke of thepistons, such as through the medium of bypassing a variable portion ofthe displacement of each discharging piston back to the inlet side ofthe device or by changing the phase relation between the reciprocatingpistons and coaoting valve porting. An example of the difference inconstruction between a xed and a variable displacement rotary axialpiston pump of this type may be found in Patents No. 2,381,056 and No.2,433,222 to M. W. Huber. An example of a radial piston device whereinthe phase relation between reciprocating pistons and coacting valveporting is yaltered to vary the displacement of the device, through themedium of rotating the Ipiston track, is shown in the patent to R.Tweedale, No. 2,237,018.

In addition to the difference in construction of the casings and pumpingassemblies of xed and variable displacement devices of the type whereinthe phase relation between piston stroking and coacting por-ting isaltered, resulting in the disadvantage of substantially increased sizeand weight of the variable displacement units over that of fixeddisplaced units, there is also present the problem of cavitation andhigh pressure impulses. When the phase relation between stroking pistonsand coacting valve porting is altered to vary the displacement of thedevice, there is a tendency for pistons on a portion of their suctionstroke to be starved, and for pistons on a portion of their dischargestroke to discharge into a path which has been closed by change in valveporting relation, thus creating high pressure impulses. Prior artdevices have v not overcome this problem by failing to provide on eitherone or the other, or on both the suction and pressure phases of thedevice, means for substantially overcoming cavitation and high pressureimpulses.

It is, therefore, an object of this invention to provide an improvedvariable displacement fluid `energy translating device of the rotaryaxial piston type.

It is another object of this invention to provide an improved variabledisplacement, rotary, axial piston uid energy translating device of thexed angle type.

It is still another object of this invention to provide an improved,variable displacement, fluid energy translating device of the rotary,axial piston type, the casing and the pump or motor assembly of whichmay be substantially and basically the same, as in conventional fixeddisplacement types of devices.

It is a further object of this invention to provide a pump head,comprising a novel valve block and plate assembly, mountable at one endof a casing of a fluid energy translating device having mounted thereinpumping mechanism of the rotary axial piston type, for varying thedisplacement of the pumping mechanism.

It is a further object of this invention to rovide for a uid energytranslating device of the rotary axial piston type, a novel valve blockand plate assembly, mountable on the casing of such device, for varyingthe dis- Y,

placement thereof without changing the length of stroke of the pistons.

It is another object of this invention to provide a pump head assemblyfor a device of the type recited in the previous object, whichv assemblyincludes a rotatably mounted valve plate with inlet and outlet portingfor the cylinder bores of the device and having a novel means forrotating the valve plate to change the phase relationship between thereciprocating pistons and the inlet and outlet porting of the device.

It is a further object of this invention to provide an improved variabledisplacement uid energy translating device of the axial piston type,which is smaller in size and weight than previous axial piston, variableuni-ts, which is economical to manufacture, and which is efficient andlong lasting.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of the present invention is clearlyshown.

In the drawings:

FIGURE 1 is a longitudinal sectional view of a fluid pressure energytranslating device embodying a preferred form of the present invention.

FIGURE 2 is an end view partially in section of a preferred form of thepresent invention.

FIGURE 3 is a sectional view taken on line 3 3 of FIGURE l.

FIGURE 4 is a sectional view taken on line 4 4 of FIGURE 1.

FIGURE 5 is a sectional view taken on line 5 5 of FIGURE l.

FIGURE 6 is a sectional view taken on line 6 6 of FIGURE l.

FIGURE 7 is a sectional View taken on line 7 7 of FIGURE l.

FIGURE 8 is a partial sectional view taken on line 8 8 of FIGURE 2.

FIGURE 9 is a sectional view taken on line 9 9 of FIGURE 4.

FIGURE 10 is a sectional View taken on line 10-10 of FIGURE 4.

FIGURE 11 is a partial sectional view taken on line 11-11 of FIGURE 3.

FIGURE 12 is a partial sectional view taken on line 12-12 of FIGURE 3.

FIGURE 13 is an enlarged sectional view of the cylinder barrel bearingpin of the device illustrated in FIG- URE 1.

FIGURE 14 is a displacement diagram illustrating the phase relationshipof valve plate porting and cylinder barrel piston stroking with thevalve plate at maximum displacement position.

FIGURE 15 is a displacement diagram, similar to that of FIGURE 14, butwith the rotor or valve plate rotated 45 from its maximum displacementposition.

FIGURE 16 is a displacement diagram, similar to that of FIGURES 14 and15, but with the rotor or valve plate rotated 90 from its maximumdisplacement position to zero displacement position.

Referring now to FIGURE 1, there is shown a iluid pump embodying thepresent invention, indicated generally by the numeral 10, comprising atwo-section casing 12 and 14, within which is mounted rotary pumpingmechanism of the well-known xed angle, axial piston type, and having apump head comprising a novel valve block and plate assembly, indicatedgenerally by the numeral 16, mounted against casing section 14, havingmounted therein rotary lluid distributing means for varying thedisplacement of the device.

The casing section 12, a portion of which is telescoped in ahollowed-out portion 13 of casing section 14, is provided with bearings18 and 20, on which a main drive shaft 22 extending from the casingsection 12 is journalled, shaft leakage being prevented by anappropriate seal 24. The drive shaft 22 carries a driving ange or thrustplate member 2.6, which carries a plurality of connecting rod sockets28, having connecting rods 30 articuated thereto, one of which is shown,the latter of which carry pistons 32 articuated by means of ball jointsat their opposite ends.

The pistons 32 reciprocate in cylinder bores 34, formed in a cylinderbarrel 36, located in a hollow portion 37 of the casing section 14adjacent to hollow portion 13 and extending slightly from the hollowportion 37, the cylinder barrel being rotatably mounted on bearings 39which are journalled on a shaft or cylinder bearing pin 38. The cylinderbarrel 36 is driven in synchronism with the drive shaft 22 by means of aCardan shaft 40 having universal joints, not shown. Each cylinder boreis provided with an individual kidney shaped port 42, shown in FIGURE 6,opening to a valving face of the cylinder barrel, indicated by thenumeral 43. The device illustrated is provided with nine cylinders andpistons and, thus, has nine cylinder ports to the cylinder barrel face43.

It should be noted that the casing and pumping mechanism of the presentdevice is typical of prior, art positive displacement, rotary lluidpumps of the xed angle, axial piston type previously described. Asviewed in FIGURE l, the left-end portion of casing section 14 extends atan angle from the remaining portions of the casing sections so that,with the valve block assembly 16 mounted against the casing section 14in the manner illustrated, the axis of rotation of the cylinder barrel36 is inclined, `relative to the axis of the thrust plate member 26.Likewise, the valve block and plate assembly 16, to be described,include a valve plate having inlet and outlet porting, against which theface 43 of the cylinder barrel 36 is adapted to rotate, and the relativeangle of inclination between the cylinder barrel and thrust plate memberaxes remains xed. The present invention, however, is concerned withproviding for, and in combination with, casing and pumping mechanism ofthe well-known xed angle type described, a novel valve block and plateassembly which may be conveniently mounted against a mounting face ofthe casing section 14 and which includes a pressure actuated rotor orrotatable valve plate for changing the phase relationship between thestroking pistons of the cylinder barrel and the valve plate inletporting for varying the displacement of the device.

Referring now to the valve block and plate assembly 16, shown in FIGURE1, the assembly comprises an outer block member 44 (FIGURES 2 and 3) andan inner pressure plate member 46 (FIGURES 6 and 7), between which issandwiched a spacer plate 48, within which is located a vane actuatedrotor having a valving face, which will also be referred to as arotatable valve plate member, and indicated by the numeral 50y (FIG-URES 4 and 5). The block, spacer and pressure plate members of theassembly are maintained together and against a plane mounting surface atthe open end of the hollow casing section 14.by means of a plurality ofbolts 52 extending from the valve block member 44, through the spacerand inner-pressure plate member, into the casing section 14. Properrelative alignment between the valve block 44, the spacer 48,inner-pressure plate member 46 and casing section 14 is provided by twoaxially disposed dowel pins 53 and two relatively longer axiallydisposed dowel pins 55, Shown in FIGURES 3, 4 and 5, the arrangementbeing more clearly illustrated in FIG- URE 8. External connection inletand outlet ports 54 and. 56

(FIGURE 2) are provided in the block member 44, which have inlet andoutlet passages 58 and 60, respectively, leading therefrom, the latterpassages having individual arcuate inlet and outlet ports 62 and 64formed at the terminus of said passages opening to a plane face 66 ofthe block member 44, as shown in FIGURE 3. The block member 44 also hasmounted therein a pressure responsive pilot valve 68 (FIGURE 2), to belater described, connected by a branch passage 70 to the outlet passage60 of the device and which is adapted to be responsive at apredetermined outlet pressure for connecting the outlet or high pressureside of the device to the rotor or rotary valve plate 50 for actuatingthe same.

Referring now to FIGURES 4 and 5, the spacer member 48 comprises a planesided plate having an axial bore 72 extending completely therethrough,which opens at one end to one face 74 thereof, which abuts the face 66of block member 44, and which opens at its other end to the face 76thereof in abutment against a face 78 of the innerpressure plate member46. O-ring seals 79 and 81 are provided for proper sealing between thevalve block and the spacer and between the spacer and the pressureplate, while an O-ring 83 seals between the casing section 14 andpressure plate 46.

The rotor or valve plate 50 is rotatably mounted within the spacer bore72 on the cylinder barrel shaft or bearing pin 38, an axial through-bore80 being constructed in the valve plate 50 and through which bore thebearing pin 38, which is supported in block member 44 within a sleevebushing 85, extends into the cylinder barrel 36. The cylinder barrelshaft or bearing pin 38 thus serves two functions, one as a journal forrotatably mounting the valve plate member 50, and the other as a journalfor the bearings 39 on which the cylinder barrel rotates. It also isprovided with a cylinder barrel lift limiting means to be laterdescribed.

As the diameter of the rotor 5t) is less than the diameter of the spacerplate bore 72, a clearance space 82 is provided between the periphery ofthe rotor 5t), indicated by the numeral 84, and the spacer bore 72,which space will be referred to as a valve plate uid pressure operatingchamber. The spacer bore 72 forms a track for the outer ends of two 180spaced apart vanes 86 and 87 mounted in substantially radial slots 88and 89 formed in the rotor S0, while the outer peripheral surface 84 ofthe rotor 50 forms a track for two 180 spaced apart vanes 90 and 91located in substantially radial slots 92 and 93 formed in the spacermember 48 (FIGURES 4, 5 and 6).

The rotor vanes 86 and 87 are resiliently preloaded in contact with thespacer bore vane track 72 and the spacer vanes 90 and 91 in Contact withthe peripheral surface 84 of the rotor 5t) by individual leafspringmembers, all of which are indicated by the numeral 94, the vanes beingrecessed for the springs, as indicated by the numeral 96, all of whichis clearly illustrated in FIGURE 9. In addition, as shown in FIGURES 4and 5, each vane slot has an angular passage associated therewith forthe purpose of connecting the high pressure portions of the valve plateoperating chamber 82 to the inner ends of the vanes for fluid pressureurging the spacer vanes outwardly against the outer periphery 84 of therotor St) and for urging the outer ends of the rotor vanes in contactwith the spacer bore 72, the vane slot angular passages in the spacermember 48 being indicated by the numeral 98, while the vane slot angularpassages in the rotary valve plate 50 are indicated by the numeral 19t).

Pressure iiuid from the outlet passage 60 is conducted to the valveplate operating chamber 82 under the control of pilot valve 68 forrotating the vane actuated rotor or valve plate 50 and also conducted tothe inner ends of the spacer an-d the valve plate vanes for urging themoutwardly in engagement with their respective vane tracks in thefollowing manner: When the pilot valve 68 is operated leftwardly, thepilot pressure passage 76, which is 6 connected to outlet passage 60,will be inter-connected to a pressure supply passage 102 (shown indotted lines in FIGURE 2), the latter of which leads from a longitudinalpilot valve bore 104. Pressure uid from the outlet side of the deviceconducted to the bore 104 and to the passage 102 from passage 70 -isthence conducted by branch pressure supply cross passages 106 and 108(FIG- URES 2 and 3) to the valve plate operating chamber 82 atdiametrically opposite points of entry, each point of entry beingbetween a nonrotatable spacer vane and a valve plate vane free to rotatewith the valve plate, the spacer and valve plate vanes being shown inFIGURE 3 by broken lines for the purpose of illustrating positionalrelationship.

The valve plate 50 is resiliently loaded to the maximum displacement,porting phase relationship shown in FIG- URES 4 and 5 by means of atorsion spring 110 (FIG- URE 1) which is coiled or mounted in circularrecesses or grooves, one located in the valve plate 50, indicated by thenumeral 112, and the other, which is indicated by the numeral 114, beinglocated in the valve block 44. The opposite ends of the torsion spring110 are imbedded in anchoring holes in the valve block and the valveplate, shown in dotted lines in FIGURES 3 and 4 and respectivelyindicated by the numerals 116 and 118.

Pressure fluid from the outlet side of the device conducted to the valveplate operating chamber 82 is adapted to impinge on the stationaryspacer plate vanes and on the valve plate vanes free to rotate with thevalve plate, and at a controlled pressure determined by the resistanceof torsion spring 110 a resultant force is created for turning the valveplate 5t) to a new position. As the control pressure increases, thevalve plate continues to rotate to new positions for decreasing thedisplacement of the pump up to 90 of valve plate rotation, which is zerodisplacement position. When the pressure decreases, the torsion springreturns the valve plate for increasing displacement.

In the present device, for decreasing displacement, the valve plate 59is rotated in the same direction as the cylinder barrel and will beclockwise, as viewed in FIG- URE 5 and counterclockwise, as viewed inFIGURE 4. As viewed in FIGURE 4, it can be seen that, as the valve plateSi) rotates, the intervane spaces in operating chamber 82, between thevalve plate vane 86 and spacer vane 91, and between the valve plate vane87 and spacer vane 99, will contract. Fluid displacement from thecontracting intervane spaces is conducted to the interior of casingsection 14, namely, the hollow portion 37 thereof, in which the cylinderbarrel rotates, by means of two diametricaliy positioned ports 119 and121 which extend from the periphery of the valve plate 59 to the recessor groove 112 in which the torsion spring is mounted, and thence bymeans of a plurality of holes 123 arranged in circular formation andwhich extend from the bottom of the groove 112 to the valve plate faceadjacent the pressure plate 46. The pressure plate 46 is provided with acentrally located axial bore 125 into which the outer end of thecylinder barrel extends for rotation against the valve plate face 76,the diameter of the bore 125 being larger than the diameter of thecylinder barrel to provide a space or chamber 127 between the peripheryof the cylinder barrel and the bore 125, with which the holes 123opening to the valve plate face 76 register, and which opens to theinterior of the casing.

A drain port 129 is provided in the casing section 14, which leads fromthe interior of the casing to the exterior thereof, and which may beconnected back to a fluid source in the conventional manner. For specialapplications and where space limitations make it linconvenient to use anexternal drain, the drain port 129 may be plugged. The interior of thecasing, in such case, is connected back to the inlet side of the deviceand also maintained at a controlled pressure above inlet pressure by adrain and case pressure control valve, indicated by the numeral 131,which is shiftably mounted in a stepped bore 133 of the valve block 44,as shown in FIGURE 1l. The upper end of the bore 133 opens to thetorsion spring chamber 114 which is connected to the interior of thecasing and the valve 131 is resiliently biased to the yclosed positionshown by a spring 135. In the position of the valve shown, the upper endof bore 133, and thus the interior of the casing, is closed fromcommunication with an angular passage 137 connected to the bore 133below the piston and which leads directly to the inlet passage 58 in thevalve block. A plug 139 closes the lower end of bore 133 and maintainsthe spring 135 in engagement against the underside of the valve 131. Thevalve 131 is thus exposed on its underside area to inlet pressure and onits upper opposed side to case pressure. When case pressure exceedsinlet pressure by an amount determined by the load of spring 135, thevalve 131 is operated downwardly, and the interior of the casing isconnected to the inlet passage 58 through the torsion spring chamber114, bore 133 and the angular passage 137. Even when the casing isexternally drained, the valve 131 may be used as a safety device in casethe external drain system for some reason fails to function properly.

For the purpose of draining the leakage at the center portion of thevalve plate around the cylinder barrel shaft or bearing pin 38 to theinterior of the casing, a plurality of axial holes 141 are provided,which are arranged in circular formation immediately adjacent thecentrally located bore of the valve plate through which the bearing pin38 extends and which register with a counterbore 143 of the valve plate,the latter of which is connected by a plurality of angular passages 145to the groove 112 of the valve plate in which a portion of the torsionspring is mounted. As previously explained, the groove or torsion springchamber 112 is connected to the interior of the casing section 14.

For the purpose of originally positioning the valve plate 50 to fulldisplacement position and for also limiting the rotation of the valveplate to 90, the Valve plate 50 is recessed to provide two diametricallyopposed, arcuately extending slots 120 and 122 (FIGURES 5 and 6) andinto which respectively, separately extend the protruding ends of twolimiting pins 124 and 126, which are respectively mounted in holes 128and 13() in the pressure plate 46 (FIGURES 6 and 10). As viewed in FIG-URE 5, the pin 124 abuts one end wall of the slot 120 while the pin 126abuts one end wall of the slot 122, for originally positioning the valveplate 50 to a resiliently loaded, full displacement position. Whenpressure fluid is conducted to the valve plate operating chamber 82 andsufficient control pressure is present, the resistance of the torsionspring 110 will be overcome and the valve plate will be rotatedcounterclockwise, as viewed in FIGURE 4. The slots 120 and 122 are ofsuch a length that, when the valve plate is turned to a position withthe pin 124 abutting the opposite end wall of slot 120 and with the pin126 abutting the opposite end wall of slot 122, the valve plate 50 Willhave been rotated 90.

Referring to the porting of the valve plate 50 and its correlation withthe block member ports and cylinder barrel ports, two opposed arcuatelyshaped ports, an inlet port 132 and an outlet port 134, are constructedin the valve plate 50, which extend axially therethrough from one face136 thereof, which is in sealing engagement with the valve block `face66, to an opposite face 138 thereof, which is in sealing engagement withthe rotary cylinder barrel face 43. As shown in FIGURE 5, the valveplate inlet port 132 and the outlet port 134, on the side 138 facing thecylinder barrel, are inverted or indented at their opposite ends,indicated by the numerals 140 and 142, for a purpose hereinafterexplained.

Referring to FIGURES 3 and 4, in the relative positions of the valveblock and the valve plate shown, inlet port 62 on the face 66 of valveblock 44 registers with the lower portion of inlet port 132 in the face136 of rotary valve plate 50, and because of its greater width overliesthe valve plate inlet port 132. The outlet port 64, in the face 66 ofvalve block 44, registers with the upper portion of outlet port 134 inthe rotary valve plate face 136. It should be noted that the inlet andoutlet ports 62 and 64 in the valve block 44 are substantially shorterin arcuate length than the inlet and outlet ports 132 and 134 of therotary valve plate 50. The valve block inlet and outlet ports 62 and 64are adapted to be of an arcuate length, relative to the length of theinlet and outlet ports 132 and 134 of the rotary valve plate 50, so thata 90 rotation of the rotary valve plate will still provide cornpleteregistration of the block member inlet and outlet ports with thecorrelated, adjacently located, rotary valve plate inlet and outletports.

For the purpose of more clearly describing the operation of the device,the cylinder ports 42 of the cylinder barrel 36, as illustrated inFIGURE 6, have been additionally provided with the numerals 1 to 9,which numerals are intended to indicate any one of the pistons withinthe cylinder bores of the cylinder barrel, as to their stroke positionrelative to the adjacent inlet and outlet ports of the rotary valveplate 50, as if the cylinder barrel was stopped in the position shown inFIGURE 6. Reference may also be made to the ow displacement diagrams ofFIGURES 14, l5 and 16, which illustrate the porting phase relationshipof the valve plate 50 and cylinder barrel 36 at different positions ofthe valve plate.

Each piston 32 of the cylinder barrel 36 will be initiating a suctionstroke when its associated cylinder port 42 is in a position indicatedby the numeral 1 in FIGURE 6 and will be completing a suction strokewhen in a position of the cylinder port indicated by the numeral 4.Also, each piston will be initiating a discharge stroke when a cylinderport is in the position indicated by the numeral 5 and will becompleting a discharge stroke when in a position of the cylinder portindicated by the numeral 8.

Thus, in the maximum displacement position of the valve plate 50 shown,the pistons within the cylinder barrel bores having associated cylinderports 42, which are located in the positions indicated by the numeralsfrom 1 to 4, will be on their suction stroke, and during the entiresuction stroke each of said pistons will be in communication with thevalve plate inlet port 132 through each of their associated cylinderports 42. The pistons associated with the cylinder ports in thepositions indicated by the numerals from 5 to 8 will be on theirdischarge stroke, and during their entire discharge stroke will be incommunication with the outlet port 134 through each of their associatedcylinder ports 42. The piston at the position indicated by the numeral 9will be at top dead center of its stroke, which in the maximumdisplacement position of the valve plate will be located between theoutlet and inlet ports, on the change-over from a discharge stroke to asuction stroke. If the cylinder barrel 36 is rotated slightlycounterclockwise from the position shown in FIGURE 6, the pistonindicated by the numeral 4 will, in the maximum displacement position ofthe rotary valve plate, be at bottom center of its stroke and at thechange-over position from its suction to its discharge stroke locatedbetween the valve plate inlet and outlet port. Unlike conventionaldevices, however, the cylinder port in the position indicated by thenumeral 9 will slightly bridge or overlap the closed area gap betweenthe inlet and outlet ports, which gap is indicated by the numeral 147,and therefore slightly overlie the inverted portions of the inlet portand the outlet ports. Likewise, when the cylinder port 4 is at bottomdead center, it will slightly bridge the lower closed gap between theports indicated by the numeral 149. This provides a slight open centercondition which aids in alleviating cavitation and high pressure surges,when the valve plate 50 is rotated and whereby pistons on a suction orpressure stroke pass through the solid gaps.

For the purpose of more clearly illustrating the phase relationship ofthe valve plate inlet and outlet ports 132 and 134 to the strokingpistons associated with the cylinder ports 42, indicated by the numerals1 to 9, reference may be made to FIGURE 14, wherein the displacementdiagram shows pistons 1 to 4 on a suction stroke in communication witht-he inlet port 132, pistons 5 to 8 on a discharge stroke incommunication with outlet port 134 and piston 9 at top dead centerposition between the inlet and outlet ports, the port 42 of piston 9being in a slightly overlapped position at its opposite ends with theinverted adjacent ends of the inlet and outlets ports 132 and 134.

The operation of the device so far described, with the rotary valveplate 50 in its maximum displacement position, is in other respectssimilar to the operation of conventional devices of this type; that is,as the cylinder barrel rotates, each piston on a suction stroke willduring its entire stroke be in communication through its associatedcylinder port 42 with the valve plate inlet or suction port 132, whileeach piston on a discharge stroke will during its entire stroke be incommunication through its associated cylinder port 42 with the Valveplate outlet or discharge port 134.

It should be noted, however, t-hat, when the valve plate 50 is rotatedclockwise from the maximum displacement position illustrated in FIGURE 5and in relation to the position of the cylinder barrel numerical portingscheme shown in FIGURE 6, the valve plate inlet and outlet ports 132 and134 will become mistimed or out of phase with the pistons of thecylinder ports 42 of the cylinder barrel, indicated by the numerals 1 to9. Each piston 32 for a portion of its suction stroke will be incommunication by means of its associated cylinder port 42 with the valveplate discharge port 134 and for a like portion of its discharge strokewill, through the same associated cylinder port 42, be in communicationwith the valve plate inlet port 132. The total displacement of thedevice for each revolution of the cylinder barrel is decreased,therefore, by an amount equal to the cubic inch displacement of eachpiston for that portion of its stroke when it is either taking in uidfrom the outlet port or discharging into the suction port of the valveplate multiplied by the number of pistons within the cylinder barrel.Reference may be made to the flow displacement diagram of FIGURE withthe valve plate rotated 45 from the maximum displacement position,wherein piston 1 initiates a suction stroke in communication with outletport 134 and with pistons 2, 3 and 4 on a suction stroke incommunication with inlet port 1132, 'while piston 5 on a dischargestroke is in communication with the inlet port 132 and pistons 6 to 9are on a discharge stroke in communication with the outlet port 134. Asthe valve plate continues to be rotated, each piston on a dischargestroke will for a greater portion of such stroke be connected to thevalve plate inlet or suction port 132 and will likewise be connected fora greater portion of its suction stroke to the valve plate dischargeport 134.

W-hen the valve plate 50 has been rotated 90, those pistons which are onthe change-over from a pressure stroke to a suction stroke and on thechange-over from a suction stroke to a pressure stroke will be passingthe center `of the valve plate inlet and outlet ports 132 and 134.Reference may be made to the flow displacement diagram of FIGURE 16,wherein pistons 1 and 2 on a suction stroke are shown in communicationwith the discharge port 134, while pistons 5 and 6 on a discharge strokeare shown in communication with the inlet port 132. At this position ofthe valve plate 50, of the total number of pistons in communication withthe valve plate inlet port through their associated cylinder ports,one-half of such pistons will be on a discharge stroke, While onehalfwill be on an intake or suction stroke, and likewise for the totalnumber of pistons in communication with the valve plate outlet port. Thepump will, at this position of the valve plate, be at Zero displacement.Each piston will initiate its suction stroke while in communication withthe outlet or discharge port 134 of the valve plate 50 and will completeits suction stroke While in communication with the valve plate inletport 132. Each piston will initiate its discharge stroke while itsassociated cylinder port is in communication with the valve plate inletport 132 and will complete its discharge stroke while in communicationwith the valve plate outlet port 134.

In the device disclosed the displacement will begin to decrease uponslight rotation `of the valve plate 50, the displacement varyingapproximately as the cosine of the angle of rotation. Thus, for everygallon of displacement after 221/2" of rotation of the valve plate fromthe maximum displacement position, the displacement will be .924 G.; at45, .707 G.; at 60, .500 G.; at 67, .382. G.; and at 0 G.

As each cylinder port 42 moves across the closed gap portions betweenthe inlet and outlet ports of the valve plate, the inverted or inwardlycurved portions and 142 of the valve plate inlet and outlet ports 132and 134 cause the cylinder ports 42 to open much faster as the ends ofthe cylinder ports leave the gap and break over the inverted portions ofthe valve plate ports. It can be seen that the inverted portconfiguration decreases the amount of restriction which would be presentif the configuration of the end portions of the ports were outwardlycurved, similar to the configuration of the end portions of the cylinderports. As there is a slight amount of overlap of the cylinder portsrelative to the closed gap portions of the valve plate (in the form ofdevice shown approximately a total of 2), when the valve plate has beenrotated to decrease the displacement of the device, high pressureimpulses are avoided as the cylinder ports of the pistons `on thepressure or discharge stroke become centrally located relative to theclosed gap portions, and also cavitation is prevented for those pistonson a suction stroke when the corresponding cylinder port is centrallylocated relative to the closed gap portions.

During operation, if a temporary critical high pressure condition iscreated, the amount of separation between the cylinder barrel and thevalve plate is limited by the cylinder bearing pin assembly arrangementshown in FIG- URES 1 and 13. The cylinder bearing pin 38 is threaded atits outer end, indicated in FIGURE 13 by the numeral 144, which extendsinto a stepped bore 146 opening to the outer-end surface of the valveblock 44. An internally threaded sleeve member 148 is adjustable on thethreaded portion of the cylinder bearing pin to preload the cylinderbarrel and rotary valve plate into proper uid sealing engagement. Forthis preloading, a spring 150- is mounted in the stepped bore 146, oneend of which engages the inner head 152 of the sleeve 148 and at itsopposite end engages a disc or washer retainer 4member 154, the latterof which engages a step of the bore 146 forming a shoulder 156. Thesleeve member 148 is originally adjusted inwardly on the threadedportion 144 of the cylinder bearing pin to engage the washer 154, whichpulls the cylinder barrel and the valve plate towards each other, and isthen slightly backed off to provide a predetermined clearance indicatedby the numeral 158 between the end of the sleeve, indicated by thenumeral 160', and the washer member 154. A jam and lock nut 162maintains the sleeve in the adjusted position, and the cylinder barreland valve plate valving faces are thus resiliently loaded into fluidsealing engagement. The open end of the stepped bore 146 is closed by anend cap or closure member 164, which is retained in the bore 146 by asnap ring 166, and an O-ring seal 168 is provided to seal the steppedbore.

As in conventional devices, the spring 150 is adapted to resilientlymaintain the cylinder barrel in iiuid sealing engagement with the valveplate. Likewise, as in conventional devices, at pressures above acritical pressure the spring is no longer able to hold the barrel on theplate.

1 1 The cylinder bearing pin assembly arrangement, therefore, providesconventional resilient preloading Without undue friction between thevalve plate and cylinder barrel, but 'also limits the amount of lift or'Separation of the barrel from the plate when critical pressure peaksare encountered. The sleeve member 148 is thus a lift limiter, becauseit limits the amount that the cylinder barrel can lift or separate fromthe valve plate to a predetermined amount, that amount being anadjustable clearance indicated by the numeral 158 between the sleeve endsurface 160 and the washer 154.

When a predetermined outlet pressure is reached and the pilot valve islactuated for conducting a controlled pressure to the operating chamberof the rotary valve plate, it is important that leakage from theoperating chamber be prevented as much as possible for the purpose ofassuring proper actuation of the rotary valve plate and within apressure range for accurate control of the same. This is provided, asshown in FIGURES l, 7 and l0, by constructing a recess and a groove inthe pressure plate, indicated by the numerals 169 and 170, which 'formsa flat ledge or shoulder 171, the recess being formed in th-e side 172of the plate 46 adjacent to the plane mounting surface at the open endof the casing section 14, indicated by the numeral 173. The plate 46 maybe made of steel, and a thin, plane sided, steel disc 174 is brazed tothe shoulder 171 which forms with the groove 170 an internal chamber175, one wall of which is the inner surface of the thin, steel discmember 174, which acts as a cover for the chamber 175. The disc 174 iscentrally perforated, indicated by the numeral 176, to mate with thecentrally located through bore 125 of the pressure plate and, inaddition, a circular slot 177 extends completely through the disc toform two lips 179 and 181, the inner surfaces of which are exposed topressure within the chamber 175 for wedging them outwardly intoengagement against the adjoining plane surface 173 of the casing section14.

Fluid pressure from the operating chamber 82 of the valve plate 50 istransmitted to the internal chamber 175 through the medium of aplurality of axial holes 183, which register with the operating chamber82 of the rotary valve plate and extend through the pressure plate 46 tothe chamber 175. The controlled operating pressure in the chamber 175exerted on the inner surface of the lips 17 9 and 181 of the disc member174 urges the same outwardly and creates a wedge-type seal between theface 172 of pressure plate 46 and end surface 173 of casing section 14.When the lips 179 and 181 of the disc member 174 are urged outwardly incontact with the casing surface 173, the pressure plate is urgedinwardly for proper sealing between the immediately adjacent surfaces 76and 78 of the spacer member 48 and rotary valve plate 50. In addition,because of the reaction forces created, the spacer and valve block areurged together to prevent any harmful leakage clearance from opening orwidening between the valve block surface 66 and spacer surface 74. Thepressure actuated wedge or lip-type sealing arrangement, therefore,provides eflicient sealing between the casing and pressure plate toprevent control pressure leakage and, in addition, tends to preventleakage paths from opening up between the opposing sides of the pressureplate and the spacer, and between the valve block end surface 66 and theadjacent spacer surface 74.

Referring now to the pilot valve indicated generally by the numeral 68,mounted within the longitudinal bore 104 of the valve block 44 is asleeve member 178, maintained against a step of the bore by a threadedclosure plug 180. A pilot valve spool 182 is shiftably mounted in a bore184 of the sleeve 178, the spool 182 being biased to the position shownby a spring 186 mounted between retainer members 188 and 190. The spring186v and retainer member 190 are mounted in the hollow section of athreaded closure and spring adjusting member 192, which closes theopposite end of bore 104. The pilot valve spool 102 is provided with'twogrooves 194 and 196 formed between spaced apart lands of the spool. Inthe position of the spool 182 shown, communication is closed between apressure delivery passage 198 of the sleeve, which is continuallyconnected to the pressure passage 70 of the valve block, and a sleevepressure delivery passage 200 continually connected to the valve blockpressure control passage 102.

When the pilot valve spool 102 is shifted leftWard-ly in response toincreases of outlet pressure greater than `the resistance of pilot valvespool spring 186, lthe groove 194 connects the sl-eeve passage 198 tothe sleeve passage 200, and pressure uid is conducted from the outletside of the pump by means of valve block passage 102 and Icross passages106 and 108 to the operating chamber 82 of rotary valve plate 50. Thepressure at which the rotary valve plate 50 is rotated is dependent uponthe resistance of torsion spring l110, a pressure drop from outletpressure in passage 70 of the valve block to a desired controlled valveplate actuating pressure occurring across the center land of the valvespool.

-In the neutral position of the valve spool shown, the operating chamber82 of the rotary valve plate 50 is connected to the interior of thecasing by means of sleeve passage 200, a sleeve passage 202 connected tothe p'assage 200 by valve spool groove 196, and a passage 204 connectedto the pilot Valve spool b-ore 184, the latter passage of which leads tothe interior of the casing. Fluid displacement from the chamber in whichspring 186 i=s mounted is connected around lche retainer 186, through ashort sleeve passage 206 -to the sleeve .passage 202, from whence it isconducted to the interior of the casing by means olf pilot valve spoolbore 184 and the passage 204.

It will thus be seen that the present invention provides a rugged,compact, low-cost, lixed angle, rotary, axial piston pump, having animproved means for varying the displacement. The displacement of thedevice is accomplished without varying the length of stroke of thepistons by utilizing a pressure operated rotatable valve plate forchanging the phase relationship between valve plate inlet yand outletpor-ting Iand the stroking pistons of the cylinder barrel. Further, theinvention provides variable displacement means comprising the block andplate assembly, which is well suited and adapted for use with presentlywell-knovvn casing and rotary, axial piston pumping structure of theiixed angle type. Unlike former rotary, axial piston devices whichutilize greatly enlarged oasings, relative to those of the dixeddisplacement type, to accommodate variable displacement structure forthe rotary, axial piston pumping mechanism, rthe present invention makesit possible to utilize the very same casing utilized for fixeddisplacement units of the same type, thus providing a great saving insize, weight and cost and also providing savings in manufacturing costsachieved by utilizing the same casing and rotary pumping mechanism forboth xed displacement and variable displacernent units. The presentinvention also provides great savings :over other types of fixed angle,variable displacement fluid pumps, wherein both the pumping mechanismand ythe casing of variable displacement units are modified as tostructure and size from those of xed displacement devices of the sametylpe. Thus, by replacing only the purnp head and valve plate of aconventional xed angle, rotary, axial piston pump with a pump headoomprising the block and plate assembly of the present invention, thereis provided a compact, rugged, economically manufactured and efficientlyoperating variable displacement device.

' While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the cllaims whichfollow.

What is claimed is as follows:

1. A fiuid energy translating device comp-rising: a hollow casing havingan axial opening at one end; means fonming a pump head secured to saidend of the casing; pumping mechanism wit-hin the casing including acylinder barrel with reciprocating pis-tons, and a uid distributingmember within the pump head, said cylinder barrel and fluid distributingmember each having a valving face; a cylinder bearing pin supported inthe pump head extending through the said axial opening into the casingand upon which both the fluid distributing member and the cylinderbarrel are rotatably mounted; means for shifting said cylinder barrelaxially toward the fluid distributing member :and for resilientlymaintaining their respective valving faces in fluid sea-ling engagementcomprising an .adjusting member threadably engaging the cylinder bearingpin, an abutment member, and resilient means located between andengaging the adjustment and abutment members; and means for limiting theamount of separation between the respective valving faces comprisingmeans forming a second abutment spaced apart from and laxiallyeoextensive with the first abutment member, said .second abutment beingadjustable to a position proximately juxtaposed with respect to thefirst abutment so as to contact the first abutment upon predetermined,limited separation of the respective vialv'ing faces.

2. A fluid energy translating device comprising: a hollow easing havingan axial opening at one end; means `forming a pump head secured lto saidend of the casing; pumping mec lanism Within the casing including acylinder barrel with reciprocating pistons, and a fluid distributingmember Within the pump head, said cylinder barrel and fluid distributingmember each having a valving face; a cylinder bearing pin supported inthe pump head extending through the said laxial opening into the casingand upon which both the fluid distributing member and the cylinderbarrel are rotatably mounted; and means for both resiliently maintainingthe valving faces in fluid sealing engagement and limiting the amount ofseparation between said valve faces comprising, an adjusting memberthreadably engaging the cylinder bearing pin, a first stationaryabutment member, resilient means disposed between and engaging theadjusting and abutment members, and means forming a second abutment:adjustable to la position proximately juxtaposed with respect to thefirs-t abutment member so as to contact the first abutment and limit theamount of separation of said waiving faces.

3. A fluid energy translating device comprising: a hollow casing havingan axial opening at one end; means fonrning a pump head secured to saidend of the casing; pumping mechanism within the casing including acylinder barrel with reciprocating pistons, and a fluid distributingmember within the pump head, slaid cylinder barrel and fluiddistributing member each having a valving face; a cylinder bearing pinsupported in the pump head extending through the fiuid distributingmember and the axial easing open-ing and upon which the cylinder barrelis rotatably mounted; means for shifting said cylinder barrel axiallytoward the fluid distributing member yand yfor resiliently maintainingtheir respective valving faces in fluid sealing engagement comprising anadjusting member threadably engaging the cylinder bearing pin, lastationary abutment member, and resilient means located 'between andengaging the adjustment and abutment members; and a second iadjust-ableabutment shiftable with said adjusting member to a position proximatelyjuxtaposed with respect to the first abutment so ras to contact thefirs-t abutment and ylimit the amount of separation between the fluiddistributing member and cylinder bar-rel Valving faces.

4. A fluid energy translating device comprising: a hollow casing havingan axial opening at one end; means forming a piunp head secured to saidend of the casing;

pumping Imechanism within the casing including a cylinder barrel withreciprocating pistons, and a liuid distribuing member within the pumphead, said cylinder barrel and uid distributing member each having avalving face; la cylinder bearing pin supported in the pump headextending through the said axial opening into the casing `and upon whichboth the fluid distributing member and the cylinder barrel are rotatablymounted; means located Within the pump bead for shifting said cylinderbarrel axially toward the fluid distributing member and for resilientlymaintaining their respective valving faces in fluid sealing engagementcomprising an adjusting member thneadlably engaging the cylinder bearingpin, an abutment member, and resilient means located between andengaging the iadjustment land abutment members; and means yalso locatedwithin the pump head `for limiting the amount of separation Ibetween therespective IVfalving faces comprising means forming a second abutmentspaced apart from and axially coextensive with the first abutmentmember, said second abutment being adjustable to la position proximatelyjuxtaposed with respect to the first abutment member so as to contactsaid first abutment and limit the amount of separation of said rvalvingfaces.

5. A fluid energy translating devicey comprising: a hollow casing havingan axial opening at one end; means forming a pump head secured to saidend of the casing; pumping mechanism within the casing including acylinder barrel with Ireciprocating pistons, and a fluid distributingmember within the pump head, said cylinder barrel and fiuid distributingmember each having a valv- Iing face; a cylinder bearing pin supportedin the pump head extending through the said :axial opening into the-oasing and upon which both the fluid distributing member and thecylinder barrel are rotatably mounted; and means located in said pumphead for both resiliently maintaining the valving faces in fluid sealingengagement and limiting the amount of separation between said valvingfaces comprising, an adjusting member threadably engaging the cylinderbearing pin, a first stationary abutment member, resilient meansdisposed between and engaging the adjusting Iand abutment members, andmeans carried by the adjusting member forming a second abutmentadjustable -to a spaced apart position proximately juxtaposed withrespect to the first abutment member so las -to contact the firstabutment 'and limit the amount of separation of said valtving faces.

6. A fluid energy translating device comprising: a hollow casing havingan axial opening at one end; means forming a pump head secured to saidend of the casing; pumping mechanism Within the casing including |acylinder barrel with reciprocating pistons, and a fluid distributingmember within the pump bead, said cylinder barrel and fluid distributingmember each 'having a valving face; \a cylinder bearing pin supported inthe pump head extending through the ruid distributing member and theaxial casing opening .and upon which the cylinder barrel is rotatablymounted; means loca-ted in the pump head lfor :shifting said cylinderbarrel axially toward the fluid distributing member and Afor resilientlymaintaining their respective v-alving faces in `fluid sealing engagementcomprising an adjusting member threadably engaging the cylinder bearingpin and including a head portion, a stationary abutment member, andresilient means located between and engaging the head portion of theadjustment member and the stationary abutment member; and a seco-ndadjustable abutment within the pump head proximvately juxtaposed withrespect to said first abutment and lcarried by and shiftable with saidadjusting member so as to contact said first abutment and limit theamount of separation between the fluid distributing member and cylinderbarrel valving faces.

(References on following page) v1 5 References Cited by the ExaminerUNITED STATES PATENTS 3/1942 Vickers et 1a1 103-162 9/1-951 Mouldm103-161 10/1955 Henrrchsen 103-161 10/1957 Shaw 121-62 16 Y 3,050,0148/1962 Sullivan 103,-42 3,073,252 1/1963 Kamps et a1. 103-162 DONLEY I.STOCKING, Primary Examiner.

5 JOSEPH H. BRANSON, JR., LAURENCE V. EFNER,

Examiners.

1. A FLUID ENERGY TRANSLATING DEVICE COMPRISING: A HOLLOW CASING HAVINGAN AXIAL OPENING AT ONE END; MEANS FORMING A PUMP HEAD SECURED TO SAIDEND OF THE CASING; PUMPING MECHANISM WITHIN THE CASING INCLUDING ACYLINDER BARREL WITH RECIPROCATING PISTONS, AND A FLUID DISTRIBUTINGMEMBER WITHIN THE PUMP HEAD, SAID CYLINDER BARREL AND FLUID DISTRIBUTINGMEMBER EACH HAVING A VALVING FACE; A CYLINDER BEARING PIN SUPPORTED INTHE PUMP HEAD EXTENDING THROUGH THE SAID AXIAL OPENING INTO THE CASINGAND UPON WHICH BOTH THE FLUID DISTRIBUTING MEMBER AND THE CYLINDERBARREL ARE ROTATABLY MOUNTED; MEANS FOR SHIFTING SAID CYLINDER BARRELAXIALLY TOWARD THE FLUID DISTRIBUTING MEMBER AND FOR RESILIENTLYMAINTAINING THEIR RESPECTIVE VALVING FACES IN FLUID SEALING ENGAGEMENTCOMPRISING AN ADJUSTING MEMBER THREADABLY ENGAGING THE CYLINDER BEARINGPIN, AN ABUTMENT MEMBER, AND RESILIENT